The SCVMM product is available today to manage Virtual Server 2005 R2 SP1. But somewhere this year, another version of SCVMM (vNext) will be available that also manages Hyper-V and VMware VI3.

What you should know about this is that SCVMM does not replace VirtualCenter. In fact, SCVMM requires VirtualCenter because it uses the VI3 APIs of VirtualCenter to do all of its work. If you have multiple VirtualCenter servers, SCVMM will be able to talk to all of them to enable management across all instances. It seems a bit too hard for Microsoft to talk to the ESX servers directly which surprises me because there are APIs to do that.

I am not sure if using SCVMM together with VirtualCenter is a compelling scenario. Sure, SCVMM's PowerShell functionality is cool but VMware itself is hard at work to get their VI PowerShell launched. VI PowerShell will beta this month and from what I have already seen it works very well.

Another SCVMM function, intelligent placement, is also something that has been available for a while on VI3. I continuously hear people say that this is a feature that SCVMM vNext will bring to VI3 and that is just incorrect. See also this article about this common misconception.

The library feature is not that interesting either because you can easily store ISOs, floppy disk images and virtual machine templates on VMFS or NFS datastores. SCVMM does provide a nicer GUI to work with those assets but that is not something that justifies an extra management tool.

I do see some benefit in the integration of SCOM 2007 with SCVMM vNext especially if Microsoft were to release a management pack for VMware VI3. Performance information from ESX hosts and virtual machines could then be fed into SCCM vNext to improve VMotion recommendations, intelligent placement calculations and so on. I don't except this will happen soon but today at the Microsoft TechDays in Ghent, a Microsoft employee told us that we should expect some big announcements around the timeframe of the Management Summit. Will there be more VMware-related integration? Time will tell...

So although I think SCVMM is great for Virtual Server and Hyper-V deployments, I don't think it is very useful in a VMware environment. But maybe you have a different opinion so let me know what you think.

You probably know that the different versions of Windows allow you to run additional virtual instances of Windows. The standard version allows you to run one additional virtual instance, the enterprise version allows four virtual instances and the datacenter version allows unlimited instances. The additional virtual instances are linked to a physical server. This means that when you buy the enterprise version of Windows for example, you can run four virtual instances on one physical server.

You should also know that these rules are not linked to Microsoft virtualization technologies such as Virtual Server or Hyper-V. They apply to VMware VI3, XenServer and any other hardware virtualization product.

But what happens in an environment with live migration features such as VMotion, XenMotion or even Quick Migration like in Virtual Server and Hyper-V? In that case you need enough licenses for the amount of virtual machines that can potentially run on one physical server.

An example should make this clearer. If you have two hosts running ESX with eight virtual machines in total and VMotion/HA enabled you might be tempted to buy two Windows Server Enterprise licenses. You can do this but then you have to run four virtual machines on one server and four virtual machines on the other and never move them! (Note: there are some exceptions to this in the official Microsoft documents)

So how many Enterprise licenses do you have to buy? The answer is you should buy four Windows Server Enterprise licenses: two for the first server and two for the second server. Depending on the amount of physical processors in the server, Windows Server Datacenter licenses will quickly become cheaper.

More information: Microsoft